A search on Frontier's website, which passengers are encouraged to check for the latest information, showed that two of the five flights from Portland to Denver on Thursday were canceled. Flight 794, scheduled to leave Portland at 8:57 a.m., and Flight 796, scheduled to leave Portland at 2:59 p.m., were canceled. Two other flights Thursday morning were just slightly delayed, and Flight 798, scheduled to leave Portland at 7:05 p.m., is listed as on time.

One flight, Flight 795, was canceled from Denver to Portland on Thursday morning and one, Flight 791, landed on time. There are three scheduled for later Thursday afternoon and all are listed as on time.

In a statement, Cliff Van Leuven, the vice president of customer service for Frontier, said: "The full impact of the damage became apparent in the light of day this morning. As we inspected our aircraft, we found several of them damaged to the point of no longer being able to fly until repairs are made.

"The timing of this damaging storm couldn't have been worse," he said. "High summer travel loads and the fact that other carriers at DIA were hit make it difficult to place passengers with other airlines, so we are doing all we can to minimize the pain of our guests' travel."